The Conservatives have struggled to weld the cuddly image of Cameron's early days as leader together with his new status as the champion of austerity. Photograph: POOL/Reuters

David Cameron retains the unfortunate ability to make the solid sound phoney and the substantial lightweight. He is – I would claim – clever, informed and tolerant. As a leader he is unflappably rooted. He knows what he stands for in a way that is unusual in modern British politics. He has an instinctive reaction to every challenge, a quick wit and wide understanding. His party has a better understanding of the need to reshape the state than either of its two rivals. It is saying some genuinely original things about social action and community self-help. It is still at that point in politics where ideas are respected internally.

It's nonsense: Brown at best is some sort of decayed shale, shattered rubble containing the odd fossil and Cameron a rather smart golden sandstone. But he certainly has a problem in that voters don't seem to see it that way. I suspect this is less to do with his personal ability and confidence – which to me seem unquestionable – than the unsettled nature of the Conservative reinvention for which he is the frontman. The problem isn't him; it's what he seems to stand for, or rather the apparent absence of sustained conviction. Cameron has been leader of the opposition for far longer than is healthy for anyone. He has passed the point where a few headline policies appear original, but not reached the stage where he can be said to have done anything in power. All he has is words.

More than that though, he suffers from having to connect two phases of his leadership into one election winning agenda. There is the modern Cameron – the pre-2008, Guardian-friendly, husky-hugging man. And then there is the leader from the age of austerity. Those two creations were unavoidable, given the economic crash. But the party has done a less good job than it should have done at welding them together. Even this week, those two different identities seemed to clash in a campaign that the Conservatives have so far dominated, almost as if the party, lacking Labour opposition, has decided to fight the campaign against itself. There is the Cameron who wants to cut national insurance and pay for it from efficency savings (a wise tax cut built on bad foundations) and the Cameron who today appeals to Guardian readers to join him.

I don't suppose many will do so, though they should think about it. I'd argue that the contradictions between these two agendas are less great than they seem, and that Cameron is serious about both. The trouble is that he hasn't found the voice to explain how and why. Of course there is a big element of rebranding about the new Tories – all those photos of Cameron jogging, and smiley-faced logos promoting the Big Society and the Great Ignored (what an ugly phrase). But he is serious about combining a smaller – but not much smaller state – with a stronger society. These two things can work together: indeed if the state is to get smaller (and even Labour thinks it will) then social action will have to step into the gap.

Cameron's sure about the destination. It isn't unattractive. But he's not an ideological man. He doesn't feel comfortable with big schemes and grand assertions. When he makes them, they sound a bit awkward; there's a note more of exasperation than persuasion in his voice. He wants to lead the common sense revolution. It seems obvious to him. But voters – as the Cameron team are fond of saying of the less modern parts of their party – just don't get it. Yet.